Portable gas detector

Abstract

The invention provides a portable gas detector of a novel structure that is easy to be fabricated as a small-sized one handy to carry and high in convenience for use. The portable gas detector has a housing in the form of a slim and flat box holdable by grasping with a hand, and a foreside half portion in the interior of he housing is provided as a functional part region, and a rear half portion in the interior of the housing is provided as a battery part region. In the functional part region, one of 5 gas sensors is arranged at a curved portion in a gas sensor-arranging region of an L shape as a whole, and 2 gas sensors are arranged in a row in both lateral and vertical directions of the above gas sensor, respectively. A gas sucking means is arranged in a region, the 2 directions of which is sectioned by the gas sensor-arranging region.

1. A portable gas detector comprising:
 a housing shaped as a slim and substantially flat box that is adapted to be grasped by a user's hand, said housing including a functional part region, in which functional members related to a gas detecting operation are arranged, at a fore-side of the housing, and a battery part region, in which a power source for driving the functional members is arranged, at a rear portion of the housing; 
 a plurality of gas sensors arranged in an L-shape, in the functional part region, such that one of the sensor is provided at a corner of the L-shape and such that a plurality of gas sensors are provided in each of two extending portions of the L-shape that. extend from the corner; 
 a gas suction mechanism which sucks gas from outside of the gas detector into the housing to be exposed to the gas sensors, and which is provided in a space at an interior of the L-shape such that the space is bordered on two sides by the two extending portions of the L-shape; and 
 a sensor cap which covers the sensort and which comprises a gas flowing path extending therethrough, a plurality of gas inlet passages corresponding respectively to the gas sensors to expose the gas sensors to the gas traveling through the gas flowing path, and an input section through which the gas sucked into the housing is input to the gas flowing path. 
 
   
   
     2. The portable gas detector according to  claim 1 , further comprising a sensor holder comprising sensor holding parts for holding the gas sensors in a plane in the L-shape. 
   
   
     3. The portable gas detector according to  claim 1  or  2 , wherein at least one of the plurality of the gas sensors comprises a contact combustion type gas sensor element, and wherein a voltage of 4.5 V is supplied from the power source. 
   
   
     4. The portable gas detector according to  claim 1 , wherein a battery chamber is formed in the battery part region in an interior of the housing so as to be openable to be exposed at a back surface of the housing, and wherein the battery chamber interchangeably holds one of: (i) 3 rod-like dry cells, and (ii) a chargeable battery pack formed by 3 chargeable batteries held in parallel by a holding frame member to have substantially a same external shape as dry the cell batteries. 
   
   
     5. The portable gas detector according to  claim 1  or  2 , wherein the gas suction mechanism comprises an exhaust flow path, and a pressure sensor is connected to the exhaust flow path and is positioned in said space at the interior of the L-shape. 
   
   
     6. The portable gas detector according to  claim 3 , wherein the gas suction mechanism comprises an exhaust flow path, and a pressure sensor is connected to the exhaust flow path and is positioned in said space at the interior of the L-shape. 
   
   
     7. The portable gas detector according to  claim 4 , wherein the gas suction mechanism comprises an exhaust flow path, and a pressure sensor is connected to the exhaust flow path and is positioned in said space at the interior of the L-shape. 
   
   
     8. The portable gas detector according to  claim 1 , wherein the sensor cap comprises an internal-Side cap member and an external-side cap member stacked on the internal-side cap member;
 wherein the gas inlet passages are formed in the internal-side cap member, which is positioned nearer to the gas sensors than the external-side cap member; and 
 wherein the gas flowing path is provided in a portion of a face where the internal-side cap member meets the external-side cap member. 
 
   
   
     9. The portable gas detector according to  claim 1 , wherein the sensor cap comprises at least one filter-installing part therein, in which a filter assembly is installed at a position corresponding to one of the gas sensors, and wherein the filter assembly adsorbs at least one interfering gas component other an object gas component to be detected by the gas sensor corresponding thereto. 
   
   
     10. The portable gas detector according to  claim 4 , wherein the battery chamber comprises a plurality of negative-side terminal armatures and a plurality of positive-side terminal armatures, and wherein each of the positive-side terminal armatures comprises:
 a central contact arm portion which is substantially U-shaped, said U-shape including two parallel portions and a linking portion linking the parallel portions, and said two parallel portions being curved; and 
 two coiled portions having a same center axis which are respectively connected to the parallel portions of the central contact arm portion.